The invention concerns an improved frame structure for washing machines, in particular top-loading or front-loading machines for household use.
For the sake of brevity and clarity, the following description and the attached drawings refer to a top-loading washing machine, but the features and the claims are applicable to washing machines of both types.
Washing machines, particularly front-loading machines, including washer assemblies, are made in various ways, generally including a rigid structure made up of a front plate, a bottom plate, two side plates, and a top. These elements are connected together in various ways, and are supported by a base or suitable feet attached to lower edges of the appliance. The base or foot support the entire weight of the apparatus, so that the appliance also supports all the internal parts of the machine. Such appliances are normally made of steel sheet metal, treated to a greater or lesser extent with chemical or electrochemical processes to improve properties of resistance to oxidation. The appliance is also painted or enameled in some cases. Such appliances are shown in European patent application no. 0,104,497, patent application GB 2,164,666, and European patent application no. 0,168,585.
Appliances manufactured in this way are normally satisfactory as far as the characteristics required by and the expectations of the consumer. The technology used for their construction has been tested and continually improved over a period of decades, but has substantially kept to the original technology of sheet-metal working. This requires appropriate support structures in stamped and worked sheet metal or the appliances must be made of particularly thick sheet metal. These alternatives have well-known technical and economic problems and require complicated and costly installations for working the sheet metal and shaping the appliance.
In addition, such washing machines lack any special structural characteristics facilitating use, construction, or recycling because the appliance itself constitutes the bearing structure and is so arranged from the beginning of the assembly process. The assembly process, as well as testing and technical support in use, is more laborious.
In fact, along with the disadvantages stated, the problem of immediate accessibility to the interior during the production phase itself has not been solved, nor have recent requirements for easy, immediate, and economical separation and recovery of the various materials been resolved.
Moreover, requirements are being imposed, by regulations or for commercial reasons, to manufacture products that are easily reusable. A large proportion of the materials of which products are composed must recyclable. Disassembly and separation of the various parts according to their physical and chemical nature, which is an indispensable part of the recycling process, must be easy, fast, safe, and economical.
Also, with the spread of more advanced technologies of industrial automation, it has become evident that simple and unhindered accessibility is a fundamental requirement with household appliances, in both assembly techniques and function testing.
Recently, especially those products made by Japanese manufacturers, plastic appliances for household washing machines have been popularized. Although said appliances have been manufactured for top-loading washing machines, they are merely a plastic version of traditional metal washing machines, with the inconveniences of the type of construction and accessibility already described.